Magnetic levitation motor and pump

Abstract

A magnetic levitation motor including a stator having magnetic bearing units and a motor unit, and a rotor provided to the stator. And the occurrence of an eddy current at a magnetic bearing is suppressed and the rotation loss of the rotor can be reduced, and also to provide a pump using such the magnetic levitation motor.

1. A magnetic levitation motor including a stator having magnetic bearing units and a motor unit, and a rotor provided to the stator, wherein:
 the stator has the motor unit between the two magnetic bearing units; 
 magnetic bearing yokes constituting the magnetic bearing units are arranged at a prescribed interval so as to draw a circle along a side surface of the rotor with a prescribed gap; 
 the magnetic bearing yoke has two salient poles facing the side surface of the rotor; 
 a magnetic bearing coil is wound around one of the salient poles, a first permanent magnet is provided to the other one of the salient poles, wherein for each of the two magnetic bearing units a second permanent magnet is provided between the motor yoke of the motor unit and the magnetic bearing unit; 
 all the salient poles provided on the motor unit side of said one of the magnetic bearing units are salient poles around which the magnetic bearing coils are wound, or are salient poles to which the first permanent magnets are provided; and 
 all the salient poles provided on the motor unit side of said other one of the magnetic bearing units are salient poles around which the magnetic bearing coils are wound, or are salient poles to which the first permanent magnets are provided. 
 
     
     
       2. The magnetic levitation motor according to  claim 1 , wherein:
 the first permanent magnets of the salient poles of said one of the magnetic bearing units, provided so as to face the rotor, have the same polarity on the rotor side; 
 the first permanent magnets of the salient poles of said other one of the magnetic bearing units, provided so as to face the rotor and so as to sandwich the motor unit, have a polarity on the rotor side that is opposite to the polarity on the rotor side in the first permanent magnets of said one of the magnetic bearing units; and 
 the second permanent magnet has a polarity on the motor unit side that is the same as the polarity on the rotor side in the first permanent magnets provided to the same magnetic bearing yokes. 
 
     
     
       3. The magnetic levitation motor according to  claim 1 , wherein:
 the first permanent magnets of the salient poles of said one of the magnetic bearing units, provided so as to face the rotor, have the same polarity on the rotor side; 
 the first permanent magnets of the salient poles of said other one of the magnetic bearing units, provided so as to sandwich the motor unit and so as to face the rotor, have a polarity on the rotor side that is the same as the polarity on the rotor side in the first permanent magnets of said one of the magnetic bearing units; and 
 the second permanent magnet has a polarity on the motor unit side that is the same as the polarity on the rotor side in the first permanent magnets provided to the same magnetic bearing yokes. 
 
     
     
       4. The magnetic levitation motor according to one of  claims 1  through  3 , wherein:
 the motor unit:
 has a motor yoke salient pole protruding from the motor yoke in a radial direction of the rotor, having a prescribed gap from the rotor, and having a motor coil wound around the motor yoke salient pole; and 
 has a motor permanent magnet on a surface of the rotor. 
 
 
     
     
       5. The magnetic levitation motor according to  claim 4 , wherein:
 the motor unit is of a consequent type. 
 
     
     
       6. The magnetic levitation motor according to  claim 1 , wherein:
 the first permanent magnet is divided and provided to the salient poles. 
 
     
     
       7. The magnetic levitation motor according to  claim 1 , wherein:
 the magnetic bearing coil is wound around each of the salient poles. 
 
     
     
       8. The magnetic levitation motor according to  claim 1 , wherein:
 a sensor for detecting a position of the rotor is provided to the magnetic bearing unit, and a control current is supplied to the magnetic bearing coil on the basis of a measurement value of the sensor. 
 
     
     
       9. A pump using the magnetic levitation motor according to  claim 1 .